Equipment Grounding Research Articles

On the question of electrical safety in physiotherapy rooms: protective grounding of electrical equipment

Abstract. The article discusses current issues of electrical safety in medical and preventive organizations. Goal: to attract the attention of physiotherapy specialists to the correct organization of protective grounding as the main means of preventing electrical injuries. Material and research: modern regulatory framework for the technical operation of electrical installations of electrical energy consumers in medical premises, the selection and use of electrical equipment and grounding devices, the frequency of inspections, measurements and tests, passports of grounding devices. Conclusion. It seems important to carry out measures to prevent accidents during the operation of physiotherapeutic equipment in each physiotherapy unit. To increase the level of organization of work on electromedical devices. Exclude the admission of personnel to the work of paramedical personnel without mandatory verification of the implementation of organizational and technical measures in the preparation of workplaces. Health care facilities should regularly hold occupational safety days, during which health care personnel should learn cardiopulmonary resuscitation skills, which today can be done in multidisciplinary accreditation and simulation centers of medical universities and academies.

Study on the Applicability of Flexible Graphite Grounding Body and Grounding Module for 500kV Transmission Line in High Altitude Area

Sichuan-Tibet Railway Changdu-Linzhi section construction power supply project (Phase II) by Tibet Power Grid Co. 4900m), the mountain is treacherous, the foundation excavation is difficult (mostly rock foundation). Among them, 3 times across 35kV lines, 1 time across 220kV lines, 1 time across the Nujiang River, across the construction is more difficult. At present, China often use galvanized steel, galvanized copper and other traditional grounding materials, due to corrosion phenomenon caused by the increase in grounding resistance, affecting the frequency current, lightning current dispersion, but also cause local stride voltage and contact voltage does not meet the requirements of the regulations, generally in 8 years need to be replaced, which greatly increases the construction cost. In order to ensure the safe operation of power equipment and the safety of staff operation, stable and highly reliable grounding materials are needed. In recent years, flexible graphite material is widely used in grounding engineering, which has good electromagnetic characteristics and strong chemical stability, not easy to be eroded by the environment, and can operate in the grounding of power equipment in a long-term and stable manner. In this paper, the soil geological structure and typical line tower grounding resistance in Tibetan area are tested and analyzed, and the flexible graphite grounding material is applied to the grounding transformation of line tower in combination with local problems in Tibet, which can reduce the burial depth of grounding electrode, and compared with the solution of using traditional grounding material, it can reduce the cost and improve the project progress, and help the construction unit and construction unit to control the budget and construction period.

Investigation of High-Speed Dynamic Transmission Error Testing Using Gear Strain

The difficulties of testing the dynamic transmission errors of gears in complex environments, such as high-speed operations or situations with oil contamination, and the limited variety of available testing methods have been recognized as issues which this study endeavors to tackle. In this study, a testing method for evaluating high-speed dynamic transmission errors of spur gears through the use of strain sensors is proposed. To reduce the interference of environmental noise on testing signals, physical measures, such as the use of copper foil to shield signal wires and the grounding of data acquisition equipment, were implemented during the testing process. Utilizing wavelet decomposition to distinguish between the high- and low-frequency components of the testing signals, the transmission error of gears during high-speed operation was calculated. After confirming the feasibility of the stress–strain stiffness approach in gear transmission error testing using the magnetic grid method, tests on modified and non-modified gears at various speeds and loads were carried out. The two types of test data were processed and evaluated to determine the effect of speed and load on gear dynamic transmission error. It was possible to conduct research on the testing technique of gear dynamic transmission errors utilizing strain sensors, which provides a new, fast, simple, and practical testing strategy for gear transmission error testing.

Analisa Hasil Pengukuran Tahanan Pentanahan Pada Peralatan di Switchyard Gardu Induk Angke PT. PLN (Persero) UIT – JBB Duri Kosambi

Substation is part of the electric power system that distributes electrical energy from the generator to the load. It is necessary to ensure safety and security guarantees for the installed equipment and humans at the substation. This research discusses the results of measuring grounding resistance on equipment in the switchyard with quantitative methods based on the results of measuring equipment grounding resistance, step voltage, touch voltage. The quantitative method is based on the quality of the equipment grounding resistance at the Angke Substation switchyard. The value of the equipment grounding resistance at the substation must be able to meet the IEEE Std standard 80 – 2000 that is < 1 ?. The smaller the grounding value obtained, the better of the grounding. Based on the results of this study, the value of the grounding resistance of the Angke Substation is 0,13 V. The value of the touch voltage is 651.55 V for humans weighing 70 kg and 481.4 V for humans weighing 50 kg. With the value of the permissible touch voltage is 626 V. The step voltage value is 2135.2 V for a human weighing 70 kg, and 1577.6 V for a human weighing 50 kg. With a permissible step voltage value of 2216 V.

경년변화에 따른 콘크리트 매입 기초접지극의 접지저항 특성분석

In accordance with the Korea Electro-technical Code(KEC), which took effect on January 1, 2021, concrete foundation rebar can be newly applied as a type of ground electrode. Using the foundation rebar of a building as a ground electrode is economically advantageous because it does not require additional grounding equipment and the structure of a typical building (rebar and steel H-beam) is easy to maintain electrical continuity. Because of these advantages, more and more building foundation rebar are being used as ground poles in actual construction.In this paper, the characteristics of grounding resistance over time when using these concrete foundation rebar as grounding electrodes in construction sites were analyzed. To this end, we proposed a plan to connect ground wires to concrete foundation rebar in two buildings under construction to measure and analyze the grounding resistance of the building over time for about four months and apply ground poles to the actual site.

Comparison of Grounding Resistance Using Grounding Rod Electrodes with Different Fault Current Types in Podzolic Soil at Prabumulih Substation

For protection against electric shock in electrical equipment, particularly in control or instrument installations in substation equipment, a quality earthing system is required. The earthing system is also affected by soil resistivity with different soil types. In the equipment grounding system, knowledge of the types of electrodes and the type of soil is required. At the Prabumulih substation, Podzolic soil is required to evaluate the stress distribution that happens in the soil in order to reduce Ground Potential Rise (GPR). In addition to obtaining the economic value of the rod electrode type employed. In this study the resistivity value of the podzolic soil type is very decisive so that the resistivity value of the podzolic soil type at the pre-selection substation land is 150 Ωm.

Health monitoring of C60 smart concrete based on self-sensing

Smart concrete is a composite material that has several advantageous characteristics such as electrical conductivity and electromagnetic shielding. It has broad application prospects in road snow and ice melting, electrical equipment grounding, structural health monitoring, and electromagnetic shielding. Thus, it is of great significance to investigate the uniaxial compressive strength (UCS) and self-sensing properties of smart concrete. In this study, two complementary properties of carbon and steel fibers were used to create functional fiber concrete. The abilities of material factors, test methods, and environmental factors to test the self-sensing capacity of concrete were investigated. Investigation of smart concrete in elastic range under stress resistivity. The results revealed that an appropriate amount of carbon and steel fibers in concrete can increase the UCS and improve self-sensing. The stress-resistivity self-sensing ability of the 0.2% carbon fiber + 0.45% steel fiber smart concrete was found to be the best. As the diameter range of the coarse aggregates increased, the self-sensing ability of the stress resistivity also increased. The environment and the measurement methods had some influence these results. When the measurement voltage was less than 5 V, the smaller the measurement voltage, the better was the self-sensing of the concrete. Concrete with a low moisture content was found to be more sensitive to stress–resistivity changes, whereas concrete with a high moisture content was more sensitive to resistivity changes under large stresses. The effect of loading speed on the self-sensing performance was relatively small. There was a good correspondence between the stress and resistivity self-sensing under cyclic unloading conditions. The resistivity decreased with an increasing load and increased with unloading, and the stability was good. The preferred carbon-steel fiber admixture for compressive-damage self-sensing concrete considering the UCS and stress-resistivity self-sensing capability was 0.2% carbon fiber+ 0.45% steel fiber. Smart concrete can be used as a stress, strain, or moisture sensor, or a load-bearing element.

Research on measurement technology of action characteristics of double-ended grounding switch based on flexible sensing

In order to solve the problems of high voltage switches’ operation characteristic tests, such as no double end grounding measurement, the inconvenient opening of grounding switch, easy injury, and equipment damage due to induced high voltage, a new measurement method is proposed in this paper, which adopts frequency conversion technology, time coding technology, and contactless flexible sensor technology, which can accurately measure the action characteristics of high voltage switch equipment under the condition of double terminal grounding. This method can effectively reduce the influence of field measurement factors and improve the accuracy, safety, and convenience of field measurement of high voltage switch action characteristics.

Analysis of a Grounding System In 20 Kv Distribution Transformer Line in PLTD Gayo Lues

The main purpose of grounding is to create a low-impedance path to the earth's surface for electric waves and transient voltages. An effective grounding system will minimize these effects. The grounding system plays a very important role in the protection system. The grounding system is used as a fault current discharge path to the ground. According to its function, grounding is divided into 2, namely grounding the neutral point of the power system and grounding equipment. The neutral grounding of the power system serves as a safety system or network, while the grounding of the equipment functions as a safety against touch voltage. Measurement of the type of grounding electrode on a 20 kV distribution transformer at PT. PLN Rema Gayo Lues Area uses 2 rod electrodes with a grounding resistance value of 2 Ohms.

Updated and expanded casualty analysis of container vessels

ABSTRACT Historical information is the key input for risk analysis with respect to developing the risk model as well as in the risk management process, i.e. identification of effective risk mitigating measures. Casualty databases are today still the primary source of this information on accidents and incidents. Accident investigation reports provide more detailed information on the accident scenario and facilitating improved risk analysis. Casualty information by IMO GISIS, IHS Markit and LMIU for the period 1990–2020 and containerships of more than 999 GT had been re-analyzed and information categorized for allowing statistical analysis of causes. A taxonomy had been developed for the consistent categorization of information and used to present accident causes in a more structured way. Appropriate statistics regarding the main causes for major types considering collision, contact, grounding, fire, explosion and failure of machinery equipment are presented in this paper. Historical trends and quantitative casualty characteristics are reported.

Basic Technology of Grounding Equipment and Lightning Protection Equipment

Basic Technology of Grounding Equipment and Lightning Protection Equipment

Selecting grounding points to reduce the interference level of the signal of high-impedance measuring channel

The study was carried out (2020) to reduce the effect of electromagnetic interference generated by a device for the formation of temperature effects based on Peltier element on a plant biopotential meter. Four variants of equipment grounding circuits are considered in the absence of a separate grounding bus for power equipment; graphs of biopotential signals are given. The type of interference that the device for the formation of temperature effects induces on the biopotential measurement channel is shown. The control unit case for the temperature-controlled stage based on Peltier element and the power cable shield for connecting Peltier element to the control unit must be grounded at a separate point from the biopotential meter. Biopotential meter electrodes should be grounded as far as possible from the control unit case and at a separate point from the grounding of the plate of the temperature-controlled stage. Recommendations are given for the grounding of high impedance input measuring devices and the power equipment emitting powerful inductive interference and causing interference in the grounding bus located in the same laboratory room, in the absence of separate grounding for power equipment. To reduce interference to an acceptable level, in addition to the selection of the grounding point, filtering is required. If the grounding point is selected incorrectly, a signal with a high level of interference is present at the filter output. The application of the proposed recommendations for grounding a device for the formation of a temperature effect based on Peltier element and a biopotential meter makes it possible to assess the response of a plant placed on the temperature-controlled stage to a temperature effect and not complicate programmed filtering of the signal received by the biopotential meter.

Appropriate Implementation of the Main Bonding Jumper and the Equipment Grounding Conductor: A Deeper Look Into a Suitable Ground Path

In many wye electrical systems, the function of the ground and neutral conductor is not differentiated because they are incorrectly joined. From a technical point of view, a connection between ground and neutral shall only be made once, at the main electrical panel; otherwise, those conductors should form two different paths. Although the implications of this connection are often seen as shallow and a misinterpretation of the National Electrical Code (NEC) makes it acceptable, this matter is actually very significant when it comes to protecting humans. Thus, it is important to take a deeper look into how to make a suitable ground path, which is the scope of this article.

Design and Test of Anti-EMI for Rail Trains

With the continuous improvement of the intelligence level of the rail transit system, the installation density of electrical and electronic equipment in rail trains becomes larger and larger, which causes the increasingly prominent electromagnetic interference (EMI) problem among any equipment, systems and subsystems. This paper proposes an anti-EMI design scheme for rail trains, which improves the anti-EMI capability of the entire train system from four aspects, i.e. equipment grounding, filtering, shielding and wiring. By taking Shanghai Metro Lines 4 and 6 as an example, we carried out the system implementation and testing. The test results show that the proposed scheme is verified to be effective and reliable to improve the electromagnetic compatibility (EMC) performance.

The Equipment Grounding System as an Effective Bonding Topology for Telecommunications Environments

Bseing provided an adequate telecommunications bonding infrastructure is one of the primary concerns for telecommunications cabling designers and installers for new and existing installations. Although not considered a safety ground where ground-fault current is concerned, the telecommunications bonding infrastructure has importance where the components are intended to equalize potentials in the event of lightning, electrostatic discharge, electromagnetic interference, and other transient events that may be imposed on it, or within telecommunications spaces. Very recently, several telecommunications design groups with varying responsibilities for data center, military encryption, and commercial facilities have explored feasible options in providing an equipotential plane for their telecommunications bonding infrastructure, especially in locations where exposed metal frame of the building is not available; the most prominent of these options being the use of the ac equipment grounding conductor system due to the abundance of metallic surface area utilized for the ac premises wiring system. This article is intended to present field-testing data and draw technical conclusions from the same so as to verify whether the equipment grounding system is viable as an alternative bonding infrastructure plane that can achieve the same effect as the standard practices in place today.

Advances and Challenges of Corrosion and Topology Detection of Grounding Grid

The grounding device plays performs the role of releasing a lightning current and a fault current in the power system, and the corrosion of the conductor will cause damage to the grounding body, which threatens the safe operation of the power system. The grounding grid corrosion detection technology and equipment guarantee the safe operation of the power system. This paper discusses the research status of grounding corrosion and topological detection in detail and introduces the basic principles, research difficulties and existing problems of the methods such as the electric network method, electromagnetic field method, electrochemical method, ultrasonic detection method and electromagnetic imaging method. The methods of electromagnetic imaging and time difference positioning proposed in recent years have been also discussed in detail. The paper points out that the application of grounding grid corrosion detection distance engineering still faces great challenges and that multi-disciplinary, multi-information fusion, new sensing technology, big data platforms and intelligent computing will be the trends to follow in research on grounding grid fault, corrosion detection and life prediction.

New Generation Tester to Assess the Electrical Safety in Low-Voltage Distribution Systems

The determination of both magnitude and duration of touch voltages is of paramount importance to protect persons against electric shock hazards, such as those caused by basic insulation failure in equipment/appliances, or direct contact with live parts. The magnitude of touch voltages depends on the impedance of the equipment grounding conductor (EGC) (also referred to as protective conductor), which should be therefore properly sized. In the US, the National Electric Code (NEC) provides minimum sizes for the EGC; however, the NEC further clarifies that the EGC selected in the specific NEC table might need be sized larger to provide adequate electrical safety. In this paper, the authors discuss the major specifications that a “new generation” tester applied to NEC based low-voltage receptacles, or live terminals of feeder/branch circuits, should possess to indicate to users if a ground-fault would cause unsafe touch potentials. Such tester should also unequivocally identify improper wiring of the outlet (e.g., phase-neutral swap, EGC-to-neutral bond).

Detection of Poor Contacts in Low-Voltage Electrical Installations

Effects of a reduced torque on heating and the electrical resistance of wire-screw terminal connections in an old (used) receptacle and two new receptacles with intentionally corroded connections were experimentally investigated in the laboratory. In one of the new receptacles, the corrosion process was accelerated by treating the line connection with a mixture of nitric acid and hydrochloric acid, and in the other by treating the neutral connection with sulfuric acid. It was shown that by using these acids, both the temperature rise and electrical behavior of long-serving receptacles can be simulated. The possibility to detect a poor contact in an electrical circuit by measuring both the line to earth (L-PE) resistance and the line to neutral (L-N) short circuit loop resistance during a periodic verification of low-voltage electrical installations was also analyzed. In the laboratory conditions, a test electrical circuit with a poor contact in each of the tested receptacles was formed and the influence of that contact on both of the mentioned resistances was observed during long-lasting heating processes. Based on the results of both the laboratory experiments and periodic verifications of low-voltage electrical installations in public and commercial buildings with the total of 11 243 receptacles, a new procedure for detecting poor contacts in low-voltage electrical installations, valid for the terra neutral protection system, is recommended. The procedure, intended for periodic verification, provides information about poor contacts and their location in the tested receptacle (on the phase, neutral, and/or equipment grounding conductor) by comparing both the L-PE resistance and the L-N short circuit loop resistance to the limit values obtained during the verification.

Calculation of two-phase ground fault current with consideration of equipment grounding specifications

The article describes ways of calculating two-phase ground fault current in electrical networks with isolated neutral for needs of calculating thermal resistance in equipment's grounding elements. Grounding resistance and metal resistance of high-voltage equipment are added to the existing methods of short circuit currents calculation.

Development of an improved earthing method for power and distribution transformers substations

Engineers and planners have realized that equipment grounding is a necessary part of installation process in Electrical power substations. Over years, grounding or earthing has been carried out primarily through preparation of Earth Mat which is interconnected with several Earth-rods buried around the equipment under consideration. This approach takes several efforts to have an acceptable and reliable result. However, this paper presents a more flexible, economical and results oriented approach. A flow chart which describes the procedures of carrying out the proposed method of earthing is developed. This was applied to two case studies: a proposed Power transformer substation and distribution Transformer substation located within the same geographical domain. On the two cases, the measured earth resistances are presented and discussed. The results from the case study indicates that the earth resistance values obtained from this new approach are reliable and in compliance with IEEE Standards 80,142, 81 and 1100. Keywords : Equipment, Grounding, Earthing, Earth-rod, Flowchart, Earth Mat, Flow Process, Injection Substation, Distribution Substation, Earth Resistance, IEEE Standard.